The overall goal of Core C (Animal Model Core) is to support the development and use of the animal models employed within this Program Project Grant (PPG). The guiding principals for the animal model core are efficient planning and utilization of animals, standardization of processing and diagnoses, reliability of service and consistent evaluation of animal models and being a cost center for all animal costs. The fundamental expertise provided within the core is laboratory animal medicine and clinical and anatomic pathology. The Core is housed and coordinated in the Department of Veterinary Biosciences. Dr. Stefan Niewiesk, proposed Core Director has been co-director of the Animal Core since 2004 and is an active collaborator with all of the principal investigators for the PPG. He is certified in Veterinary Microbiology and as a Laboratory Animal Medicine Veterinarian (European). Because of Dr. Niewiesk's unique training, he also provides expertise in the generation of monoclonal and polyclonal antibodies for specific projects for the PPG. Dr. Thomas Rosol (Project 4, Co-Pi), who is certified by the American College of Veterinary Pathologist will serve as co-director for the Core. These investigators are joined by experienced technical staff to form a highly experienced professional team to guide the Core and meet the goals of the PPG investigators. A common thread among all research groups is the shared use of unique infectious molecular clones of HTLV-1 and HTLV-2, developed or characterized in our laboratories and links to established animal models to test molecular determinants of disease. Since 2003, the investigators have further evolved multiple new interdependent methods, techniques, and synergistic exchanges that serve to integrate their science to approach basic biological paradigms as desired outcomes from the project laboratories. The highly interactive Animal Core directed by Dr. Niewiesk will provide a central purchasing and procurement method to facilitate animal studies and to reduce redundancy and promote collaborations among the projects. A unique role of the Animal Core will be to provide faculty with expertise in mouse pathology, and provide state-of-the-art methods to determine and quantify bone lesions.